If you're looking to save money on your cell phone plan, now may be a good time to shop around. More companies are lowering their rates. But make sure you understand the fine print.

To begin with, Consumer Reports recommends that you be open to switching your cell phone provider. A Consumer Reports survey last year found that people had been with their current cell phone company for an average of eight years. And if they did switch, more than half said it was to save money.

That, along with user demands and competition, have the major carriers looking for an edge. And right now, that edge appears to be creating unlimited phone plans.

AT&T, T-Mobile and Verizon are now all offering what they call unlimited plans that start at $40 per line, per month, if you have four lines. If not, the price increases. Sprint is offering four lines for $22.50 per line, per month, but that discounted price is only for a limited time.

"There's a lot of movement around unlimited and all of the major carriers are offering changes or plans that cover unlimited data structures," said Scott Peterson, a senior analyst with Gap Intelligence.

He said when you study all of the unlimited offers on the market, you quickly discover they are not all the same.

"My best advice for individual consumers would be to monitor their personal data usage and find a plan that fits that, rather than going all in for unlimited, because that's what the marketing tells us,” Peterson said.

Peterson also said despite the name, unlimited plans can limit connection speeds, screen resolution, hot spot capabilities and other features. This trend is affecting overall performance, according to him.

"Download speeds of the major carriers are fading, based on more people jumping on unlimited plans,” Peterson said. “Consumers need to be aware of what their own needs are. I hear unlimited -- I want it. Give me. Give me. But do I need it? Absolutely not."

Many so-called unlimited plans slow down your data after you use a set amount of it. That basically means, it becomes hard to stream TV and movies and create a hotspot.